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Partition coefficient

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Reference
Endpoint:
partition coefficient
Type of information:
experimental study
Adequacy of study:
key study
Study period:
From 14 February 2018 to 27 February 2018
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
guideline study
Qualifier:
according to guideline
Guideline:
OECD Guideline 107 (Partition Coefficient (n-octanol / water), Shake Flask Method)
Deviations:
no
Qualifier:
according to guideline
Guideline:
EU Method A.8 (Partition Coefficient - Shake Flask Method)
Deviations:
no
GLP compliance:
yes (incl. QA statement)
Type of method:
flask method
Partition coefficient type:
octanol-water
Analytical method:
high-performance liquid chromatography
Key result
Type:
log Pow
Partition coefficient:
ca. 2.62
Temp.:
20 °C
pH:
>= 6.34 - <= 6.74

The test item stock solution was prepared in 1-octanol water pre-saturated with water.The measured1-(2,4-dichlorophenyl)ethanoneconcentration in stock solution (1-octanol)was6.3400g/kg (5.2305 g/L). Density of 1-octanol (supplier data) is 0.825 g/L.

 

Table 1: Calibration solution

Weight

[mg]

Dilution

[mL]

Cw

[mg/mL]

Peak area

Average

peak area

Aw

f

Average

 f

20.15

25-0.2-25

0.00064287

59165

59177

59171

0.00001086

0.00001103

25-1.0-25

0.00642866

573687

573772

573729,5

0.00001121

Table 2: Study solution

Sample

 

Weight

of the sample

[mg]

Dilution

[mL]

Cp

[mg/mL]

Peak area

 

Average peak area

Ap

X

[g/kg]

1/w

2020.45

5

404.09

95980

95817

95898.5

0.0026

2/w

2019.20

5

403.84

94897

95489

95193.0

0.0026

3/w

2024.55

5

404.91

142467

142981

142724.0

0.0039

4/w

2034.10

5

406.82

139506

140905

140205.5

0.0038

5/w

1972.25

5

394.45

44842

44540

44691.0

0.0013

6/w

1987.25

5

397.45

60949

60431

60690

0.0017

stock

82.1

10-0.1-10

0.0821

47026

47314

47170.0

6.3400

1/o

80.25

10

8.025

851148

851893

851520.5

1.1709

2/o

82.40

10

8.240

847056

847264

847160.0

1.1345

3/o

85.55

10

8.555

1361771

1369506

1365638.5

1.7615

4/o

82.85

10

8.285

1322661

1322353

1322507.0

1.7614

5/o

76.80

10

7.680

693863

696989

695426.0

0.9992

6/o

83.35

10

8.335

683212

660035

671623.5

0.8892

Table 3: Results of measurements at 20.0°C

Vial number

1

2

3

4

5

6

Temperature,                                  °C

19.9

19.9

20.0

Volume of added stock solution,   mL

1

1

1

1

1

1

Volume of water,                           mL

5

5

6.7

6.7

3.3

3.3

Volume of 1-octanol,                      mL

4

4

2.3

2.3

5.7

5.7

Volume 1-octanol phase/

volume of water phase

1:1

1:2

2:1

1-(2,4-dichlorophenyl)ethanone concentration in water phase,         g/L

0.0026

0.0026

0.0039

0.0038

0.0013

0.0017

1-(2,4-dichlorophenyl)ethanone concentration in 1-octanol phase, g/kg

1.1709

1.1345

1.7615

1.7614

0.9992

0.8892

1-(2,4-dichlorophenyl)ethanone concentration in 1-octanol phase,   g/L

0.9660

0.9360

1.4532

1.4532

0.8243

0.7336

Mass of1-(2,4-ichlorophenyl)ethanone in water phase103,                          g

0.0130

0.0130

0.0261

0.0255

0.0043

0.0056

Mass of1-(2,4-ichlorophenyl)ethanone in 1-octanol phase103,                    g

4.8300

4.6800

4.7956

4.7956

5.5228

4.9151

Mass of1-(2,4-ichlorophenyl)ethanone in both phases103,                              g

4.8430

4.6930

4.8217

4.8211

5.5271

4.9207

Added mass of1-(2,4-dichlorophenyl)ethanone103, g

5.2305

5.2305

5.2305

5.2305

5.2305

5.2305

Table 4: Measured pH values of water phase

        Vial number

1

2

3

4

5

6

pH before test

6.15

6.15

6.15

6.15

6.15

6.15

pH after test

6.66

6.67

6.36

6.34

6.74

6.70

Table 5: Calculated values of partition coefficient 1-octanol/water

Vial number

1

2

3

4

5

6

Volume 1-octanol phase/volume of water phase

 

1:1

 

1:2

 

2:1

Pow= C1-octanol/Cwater

371.54

360.00

372.62

382.42

634.08

431.53

log Pow= log(C1-octanol/Cwater)

2.57

2.56

2.57

2.58

2.80

2.64

Average log Pow+ standard deviation

2.57 ± 0.01

2.58 ± 0.01

2.72 ± 0.11

Average log Pow+ standard deviation

2.62±0.08

Conclusions:
The calculated value of logarithm to the base 10 of the test item partition coefficient 1-octanol/water (log Pow) at 20.0 ºC and at pH ranging 6.34 - 6.74 is 2.62 ± 0.08.
Executive summary:

The determination of partition coefficient 1-octanol/water was performed according to OECD 107 and EU method A.8 (flask method), following GLP. The concentrations of test item were determined in both phases by HPLC method, using a liquid chromatograph Spectra-Physics. The calculated value of logarithm to the base 10 of the test item partition coefficient 1-octanol/water (log Pow) at 20.0 ºC and at pH ranging 6.34 - 6.74 is 2.62 ± 0.08.

Description of key information

Key study: OECD 107 and EU method A.8. GLP study. The calculated value of logarithm to the base 10 of the test item partition coefficient 1-octanol/water (log Pow) at 20.0 ºC and at pH ranging 6.34 - 6.74 is 2.62 ± 0.08.

Key value for chemical safety assessment

Log Kow (Log Pow):
2.62
at the temperature of:
20 °C

Additional information

Key study: The determination of partition coefficient 1-octanol/water was performed according to OECD 107 and EU method A.8 (flask method), following GLP. The concentrations of test item were determined in both phases by HPLC method, using a liquid chromatograph Spectra-Physics. The calculated value of logarithm to the base 10 of the test item partition coefficient 1-octanol/water (log Pow) at 20.0 ºCand at pH ranging 6.34 - 6.74 is 2.62 ± 0.08.